49 CFR § 501.5 - Exercise of authority.
(a) All authorities lawfully vested in and reserved to the Administrator in this title, part, or other NHTSA regulation or directive may be exercised by the Deputy Administrator and, in the absence or disability of both officials, by the Chief Counsel, unless specifically prohibited by statute, regulation, or order.
(b) In exercising the powers and performing the duties delegated by this part, officers of NHTSA and their delegates are governed by applicable laws, executive orders, regulations, and other directives, and by policies, objectives, plans, standards, procedures, and limitations as may be issued from time to time by or on behalf of the Secretary of Transportation, the Administrator, the Deputy Administrator, the Chief Counsel, and the Executive Director or, with respect to matters under their jurisdiction, by or on behalf of the Associate Administrators, the Regional Administrators, and the Directors of Staff Offices.
(c) Each officer to whom authority is delegated by this part may redelegate and authorize successive redelegations of that authority subject to any conditions the officer prescribes.
(d) Each officer to whom authority is delegated will administer and perform the functions described in the officer's respective functional statements.